Math = Love: Accuracy, Precision, Error, and Percent Error INB Pages

## Thursday, September 1, 2016

### Accuracy, Precision, Error, and Percent Error INB Pages

Our second skill of the year in Physical Science is to differentiate between accuracy and precision and calculate error and percent error.  I'm calling this unit "The Mathematics of Science."  Given that I'm a trained math teacher and not a science teacher, it's probably the unit I'm most qualified to teach.
Though, I'll have to admit that I had to read up on accuracy and precision since it's not something I've really thought about since I was in high school science!

First, we wrote definitions for accuracy and precision.  I could tell that my students were writing these definitions down without really thinking about what they meant.

Next, I gave my students pictures of four targets.  I found these target pictures on the New Zealand Science Learn website.  Here's a direct link to the file.

Once we started trying to label these as accurate/not accurate and precise/not precise, the definitions started to make a lot more sense to my students!  They were a bit bummed when I told them that on their quiz they were going to have to do the same thing with numbers instead of targets.

Next, we moved into a discussion of error and percent error.  We talked about how mis-measuring someone's height by a foot and mis-measuring the height of a mountain by a foot were completely different circumstances.

I got a bit confused on the formula for error.  I found some resources that defined error as the difference in measured value and accepted value.  Other resources defined error as the difference in accepted value and measured value.  I decided to just use the absolute value of the difference of the two values since I don't feel confident enough choosing one way over the other.  Plus, we'll be using the absolute value anyway when we calculate percent error.

The problems from this foldable are taken from the Chemistry Workbook for Dummies book (affiliate link).  So far, I've found the book to have really approachable, clever practice problems.

Outside of Booklet Foldable:

Inside of Booklet Foldable:

Close-up 1:

Close-up 2:

I've also started prepping for our first lab of the year.  I printed off these targets and laminated them with my handy, dandy, new pink laminator.

I've had a Scotch brand laminator (affiliate link) for a few years that I love, but I recently bought a second laminator so I can keep one at school and one at home.  Amazon ran a special the other day, and I was able to pick up this Swingline laminator (affiliate link) for only \$15.99.  As of the time of this blog post, it's currently \$22.75 which I think is still a steal for a laminator!  This Swingline laminator has a really short warm-up period that is only about four minutes.  It seems to warm up much faster than my Scotch laminator.  It also is SUPER quiet.  The one thing the Scotch laminator has going for it, though, is speed.  I was pretty tickled when Shaun agreed to let me order the pink laminator last week!  (It also comes in gray, blue, and red.)  Though, he did insist that this be the laminator we kept at home.  I wonder why...

Okay.  Enough laminator talk.  Back to my plan with the targets.  I'm planning on having my students drop dry erase markers on the target from a certain distance above.  After doing this a certain number of times (AKA I haven't actually figured out how many!), students will describe the accuracy and precision of their work.  Then, we'll break out the rulers and calculate their error and percent error.  This could go either really well or terribly.  I'll be sure to report back!  It's inspired by page 3 of this file.

If you're interested in the files in this post, you can find them here!